class Calculator():
    __result = 0 

    @classmethod
    def __init__(cls, init_value):
        cls.__result = init_value

    def return_cls(func):
        def inner(*args, **kwargs):
            func(*args, **kwargs)
            return args[0]
        return inner

    @classmethod
    @return_cls
    def clear(cls):
        cls.__result = 0
        return cls

    @classmethod
    @return_cls
    def show(cls):
        print(cls.__result)
        return cls

    @classmethod
    @return_cls
    def plus(cls, value):
        cls.__result += value

    @classmethod
    @return_cls
    def division(cls, value):
        print(cls)
        cls.__result /= value

    @classmethod
    @return_cls
    def multiply(cls, value):
        cls.__result *= value

    @classmethod
    @return_cls
    def subscribe(cls, value):
        cls.__result -= value

Calculator(1).plus(2).division(2).multiply(5)   \
.show()

